Android Open Source - SimpleNotes Settings Activity

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License

The source code is released under:
Apache License
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Java Source Code

package com.moysa.simplenotes.ui.activities;
/*w w w  .j  a v a2s.  c o m*/
import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.Configuration;
import android.os.Build;
import android.os.Bundle;
import android.preference.*;
import android.view.MenuItem;
import com.moysa.simplenotes.R;

import java.util.List;

/**
 * A {@link PreferenceActivity} that presents a set of application settings. On
 * handset devices, settings are presented as a single list. On tablets,
 * settings are split by category, with category headers shown to the left of
 * the list of settings.
 * <p/>
 * See <a href="http://developer.android.com/design/patterns/settings.html">
 * Android Design: Settings</a> for design guidelines and the <a
 * href="http://developer.android.com/guide/topics/ui/settings.html">Settings
 * API Guide</a> for more information on developing a Settings UI.
 */
public class SettingsActivity extends PreferenceActivity {
    /**
     * Determines whether to always show the simplified settings UI, where
     * settings are presented in a single list. When false, settings are shown
     * as a master/detail two-pane view on tablets. When true, a single pane is
     * shown on tablets.
     */
    private static final boolean ALWAYS_SIMPLE_PREFS = false;
    /**
     * A preference value change listener that updates the preference's summary
     * to reflect its new value.
     */
    private static Preference.OnPreferenceChangeListener sBindPreferenceSummaryToValueListener = new Preference.OnPreferenceChangeListener() {
        @Override
        public boolean onPreferenceChange(Preference preference, Object value) {
            String stringValue = value.toString();

            if (preference instanceof ListPreference) {
                // For list preferences, look up the correct display value in
                // the preference's 'entries' list.
                ListPreference listPreference = (ListPreference) preference;
                int index = listPreference.findIndexOfValue(stringValue);

                // Set the summary to reflect the new value.
                preference.setSummary(
                        index >= 0
                                ? listPreference.getEntries()[index]
                                : null
                );
            } else {
                // For all other preferences, set the summary to the value's
                // simple string representation.
                preference.setSummary(stringValue);
            }
            return true;
        }
    };

    /**
     * Helper method to determine if the device has an extra-large screen. For
     * example, 10" tablets are extra-large.
     */
    private static boolean isXLargeTablet(Context context) {
        return (context.getResources().getConfiguration().screenLayout
                & Configuration.SCREENLAYOUT_SIZE_MASK) >= Configuration.SCREENLAYOUT_SIZE_XLARGE;
    }

    /**
     * Determines whether the simplified settings UI should be shown. This is
     * true if this is forced via {@link #ALWAYS_SIMPLE_PREFS}, or the device
     * doesn't have newer APIs like {@link PreferenceFragment}, or the device
     * doesn't have an extra-large screen. In these cases, a single-pane
     * "simplified" settings UI should be shown.
     */
    private static boolean isSimplePreferences(Context context) {
        return ALWAYS_SIMPLE_PREFS
                || Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB
                || !isXLargeTablet(context);
    }

    /**
     * Binds a preference's summary to its value. More specifically, when the
     * preference's value is changed, its summary (line of text below the
     * preference title) is updated to reflect the value. The summary is also
     * immediately updated upon calling this method. The exact display format is
     * dependent on the type of preference.
     *
     * @see #sBindPreferenceSummaryToValueListener
     */
    private static void bindPreferenceSummaryToValue(Preference preference) {
        // Set the listener to watch for value changes.
        preference.setOnPreferenceChangeListener(sBindPreferenceSummaryToValueListener);

        // Trigger the listener immediately with the preference's
        // current value.
        sBindPreferenceSummaryToValueListener.onPreferenceChange(preference,
                PreferenceManager
                        .getDefaultSharedPreferences(preference.getContext())
                        .getString(preference.getKey(), "")
        );
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);

        getActionBar().setDisplayHomeAsUpEnabled(true);

        setupSimplePreferencesScreen();
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            // Respond to the action bar's Up/Home button
            case android.R.id.home:
                this.finish();
                return true;
        }

        return super.onOptionsItemSelected(item);
    }

    /**
     * Shows the simplified settings UI if the device configuration if the
     * device configuration dictates that a simplified, single-pane UI should be
     * shown.
     */
    private void setupSimplePreferencesScreen() {
        if (!isSimplePreferences(this)) {
            return;
        }

        // In the simplified UI, fragments are not used at all and we instead
        // use the older PreferenceActivity APIs.

        // Add 'general' preferences.
        addPreferencesFromResource(R.xml.pref_general);

        // Bind the summaries of EditText/List/Dialog/Ringtone preferences to
        // their values. When their values change, their summaries are updated
        // to reflect the new value, per the Android Design guidelines.
        bindPreferenceSummaryToValue(findPreference("sort_list"));
        bindPreferenceSummaryToValue(findPreference("sort_type_list"));
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean onIsMultiPane() {
        return isXLargeTablet(this) && !isSimplePreferences(this);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    public void onBuildHeaders(List<Header> target) {
        if (!isSimplePreferences(this)) {
            loadHeadersFromResource(R.xml.pref_headers, target);
        }
    }

    /**
     * This fragment shows general preferences only. It is used when the
     * activity is showing a two-pane settings UI.
     */
    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    public static class GeneralPreferenceFragment extends PreferenceFragment {
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            addPreferencesFromResource(R.xml.pref_general);

            // Bind the summaries of EditText/List/Dialog/Ringtone preferences
            // to their values. When their values change, their summaries are
            // updated to reflect the new value, per the Android Design
            // guidelines.
            bindPreferenceSummaryToValue(findPreference("sort_list"));
            bindPreferenceSummaryToValue(findPreference("sort_type_list"));
        }
    }
}
Java Source Code List
